Internal combustion engines, such as diesel engines, are known to utilize exhaust back pressure control systems to improve engine warm-up, particularly in cold environments. A diagram of such a system is shown in FIG. 1. A turbocharger comprising a compressor 101 operating in conjunction with a turbine 103 via a common shaft has an exhaust valve 105 that rotates between open and closed positions as directed by a pivot shaft rod 107. When a cylinder 109 is pressurized, a piston within the cylinder 109 moves a rod 111 that is attached to a ball joint linkage 113 that is in turn attached to a crank 115. The axial movement of the rod 111 is converted to rotational movement of the crank 115 by the ball joint linkage 113, resulting in rotation of the pivot shaft rod 107, which opens and closes the valve 105. By closing the valve 105, the engine is forced to work harder against the exhaust pressure build up, thereby warming up faster.
A diagram illustrating a cross-sectional view of the cylinder 109 is shown in FIG. 2. A single-acting hydraulic cylinder 109 with a spring return is illustrated. A hydraulically operated piston 201 compresses a spring 203 and moves the rod 111 to move the rod 111 in order to open and close the valve 105 of FIG. 1. One or more washers 205 are utilized to provide a rudimentary seal between the rod 111 and the cylinder 109. Because no rod guide bearing is utilized, the rod 111 moves axially, radially, and/or in other directions within the cylinder. With age and repeated use of the piston 201, the washer 205 eventually wears out, and oil leakage may result.
Accordingly, there is a need for a seal that does not leak when the seal is utilized in conjunction with a rod that moves axially, radially, and/or in other directions within the cylinder.